EP0405083B1 - End cross seal for controllable deflection roller - Google Patents

Description

The invention relates to an end cross seal of the type corresponding to the preamble of claim 1.

Such an end cross seal serves to seal the space between the incoming hollow roller and the fixed crosshead in the axial direction against an internal pressure. The internal pressure can arise if the hydraulic support device consists of a semi-cylindrical shell-shaped chamber filled with hydraulic fluid, which is separated from the remaining space by the end cross seals and longitudinal seals attached to both sides of the cross head, as is the case with JP-Y-62 on which the preamble is based -17520 is the case. A similar end cross seal is also shown in DE 20 25 777. In the aforementioned cases, in which the end cross seal delimits a so-called S-roll chamber, which is divided by longitudinal seals, the end cross seal extends over approximately 180 ° in the circumferential direction. This also applies to the case of DE-A-30 03 395, in which the pressure in the S-roll chamber is modified by sealing members which omit zones of lower pressure.

However, there are also cases in which the entire space between the hollow roller and the crosshead is filled with pressure fluid over 360 °, as shown in DE-A-36 40 902. In these cases, of course, the end cross seal extends over 360 °.

In many cases, the pressure against which the end cross seal is to seal is several 10 bar. The peripheral speed on the abutting sliding surfaces can be up to 1000 m / min, and finally the hydraulic pressure fluid can have a temperature of 250 ° C or more. It has been found that under these difficult conditions, the pressure fluid on the pressure side tends to penetrate radially from the outside from the sliding ring and to lift it off the stationary counter ring, which naturally impairs the sealing effect.

The invention has for its object to suppress this phenomenon. This object is achieved by the invention reproduced in claim 1.

It is hereby achieved that the amounts of liquid which have penetrated radially from the outside on the sliding surface are immediately drained off to the low-pressure side and no more lifting pressure can build up in the sliding surface. The slide ring lies perfectly on both sides of the chamber, which serves to relieve the slide ring pressed against the sliding surface under the high pressure on the overpressure side, and is thus able to perform its sealing function properly.

The slide ring can be designed and sealed in detail in the manner that can be taken from claim 2. It has been found that a perfect seal of the slide ring against the crosshead, in contrast to which it must be displaceable in the event of deflections of the hollow roller and in particular the crosshead, can be achieved in this way.

The ring, which rests against the approach of the slide ring from the inside, can in particular consist of polytetrafluoroethylene, because this is a material which is easy to slide and at the same time to a certain extent conformable.

The connection of the groove to the low-pressure side can be formed in this embodiment according to claim 4 by a channel which extends substantially axially through the slide ring, generally through a corresponding bore.

If the chamber is divided into several individual chambers in the circumferential direction and gaps remain between them, there is another possibility of establishing a connection between the groove and the low-pressure side, in the configuration shown in claim 5.

Channels leading radially inwards from a groove of an end transverse seal are known per se from DE-A-38 13 596, which belongs to the prior art but is not prepublished. However, this is not a mechanical seal in which an axial pressure takes place. The seal known from DE-A-38 13 596 is rather hydraulically pressed radially against the inner circumference of the hollow roller, and the radial channels serve to branch off the pressure necessary for hydraulic relief of the sliding surfaces.

• Fig. 1 zeigt einen Teillängsschnitt durch das rechte Ende einer durchbiegungssteuerbaren Walze mit der erfindungsgemäßen Endquerdichtung;
• Fig. 2 zeigt eine Teilansicht eines über 180° gehenden Bereichs der Endquerdichtung gemäß der Linie II-II in Fig. 1;
• Fig. 3 und 4 zeigen Schnittansichten nach den Linien III-III und IV-IV in Fig. 2.

Exemplary embodiments of the invention are shown in the drawing.

• Fig. 1 shows a partial longitudinal section through the right end of a deflection-controllable roller with the end cross seal according to the invention;
• FIG. 2 shows a partial view of a region of the end transverse seal extending over 180 ° according to the line II-II in FIG. 1;
• 3 and 4 show sectional views along the lines III-III and IV-IV in Fig. 2nd

The roller designated 100 in FIG. 1 as a whole comprises an non-rotatable crosshead 1, around which a hollow roller 2 rotates, which forms the working roller circumference 3 and which, with its inner circumference 4, remains at a distance from the outer circumference 5 of the crosshead. The hollow roller 2 is supported at the ends on spherical roller bearings 6 on the crosshead 1. Between the spherical roller bearing 6 and a step 7 on the inner circumference 4 of the hollow roller 2, a counter ring 8 is clamped, which rotates with the hollow roller 2, surrounds the crosshead 1 and, on the side facing inwards, provides a sliding surface 9 perpendicular to the axis of the hollow roller 2 which rests on the crosshead 1, which is movable relative to it within a certain range, but is otherwise stationary, in a sealing manner.

The slide ring 10 has a substantially rectangular cross section and is arranged in front of a diameter step 11 of the crosshead. It overlaps the diameter step 11 with an externally provided axial shoulder 12. In the area in which the shoulder 12 overlaps the diameter step 11, a radially outwardly open circumferential groove 13 is provided in the groove, on the bottom of which an O-ring 14 and above Ring 15 of substantially rectangular cross-section made of polytetrafluoroethylene are arranged. The ring 15 lies with its outer side sealingly against the inner circumference 16 of the shoulder 12. There is little play between the inner circumference 16 and the adjacent outer circumference of the crosshead 1, so that the sliding ring 10 can shift somewhat relative to the crosshead 1 in order to take account of the deflection of the crosshead 1 when the roller 100 is loaded.

The slide ring 10 is pressed against the counter ring 8 by axial helical compression springs 17 lying in front of the diameter step 11 and prevented from rotating by screws 18 distributed over the circumference.

On the side facing the sliding surface 9, the sliding ring 10 has a plurality of chambers 19, which together take up almost the entire circumference, and which, with the high-pressure space 20 between the inner circumference 4 of the hollow roller 2 and the outer circumference 5 of the crosshead 1, each have one in Fig. 1 are only schematically indicated throttled channel 21 in connection.

The detailed design is shown in FIGS. 2 and 3. The channel 21 consists of an axially extending bore 22 which opens into the chamber 19 and is closed at the other end by a plug 24. Between the stopper 24 and the chamber 19 there is a radial bore 23 which communicates with the pressurized intermediate space 20 and which brings in the pressure fluid which passes throttled into the chamber 19 through a throttle insert 25 provided in the bore 22.

As can be seen from FIG. 2, there are six chambers 19 distributed over the circumference in the exemplary embodiment, each of which is connected to the intermediate space 20 by a channel 21.

Radially outside the chambers 19, in a face of the slide ring 10 facing the slide surface 9, near the outer edge of the slide surface 9 and only a few millimeters away, there is a narrow groove 30 of 360 mm, for example 3 mm deep and wide, which extends over a or several channels 26 only indicated in FIG. 1 and shown in detail in FIG. 4 is connected to the low-pressure side, ie in the exemplary embodiment to the other end face 36 of the slide ring 10 which is remote from the sliding surface 9 and which is separated from the intermediate space carrying the high pressure 20 is separated by the pair of sealing rings 14, 15. The end face 36 has an axial distance from the diameter step 11. Likewise, the inner circumference 37 of the slide ring 10 has a radial distance from the adjacent area of the crosshead 1. Hydraulic fluid passing through the channel 26 can therefore flow through these spacing spaces. In this way, at the point 27 in FIG. 4, hydraulic fluid penetrating into the intermediate space 20 under the high pressure is immediately drained off before it can lift the sliding ring 10 off the sliding surface 9, as a result of which the perfect sealing and sliding effect on the sliding ring 10 in the region the chambers 19 remains unaffected.

The leakage liquid which has passed from the high-pressure intermediate space 20 on the sliding surface 9 and on the seal 15 can be sucked off through a channel 28.

An alternative to the channels 26 is indicated in FIG. 2, which is, however, only possible if the chamber 19 does not pass over the circumference, but rather individual chambers 19 are present, each of which occupy only one segment of the circumference and a spacing space 31 between them leave. Through this space, a radial groove 32, which is open towards the sliding surface 9, can be carried out from the circumferential groove 30 to the inside, which is also able to relieve the pressure in the groove 30 by providing access to the low-pressure side . The adjacent chambers 19 must not be cut, i.e. they must be closed in all directions in the sliding plane 9, otherwise they cannot perform their function.

The hollow roller 2 is closed at the end by a cover 33 which is connected to the hollow roller 2 by means of screws 34. The cover 33, which rotates with the hollow roller 2, is sealed off from the crosshead 1 by a further mechanical seal 35, which, however, does not have to seal against particularly high pressure, but is only intended to prevent pressure fluid from escaping from the roller.

Claims (5)

1. An end transverse seal for a controlled deflection roll (100),
         having a rotating shell (2) effective as the operative periphery (3) of the roll and a non-rotating beam (1) which extends through the shell (2) over the length thereof and at a distance from its inner periphery (4),
         and hydraulic support means which act on the shell inner periphery (4) and are disposed on the beam (1),
      one end transverse seal (8, 10) being disposed at each end of the shell (2) and sealing off from the outside the high-pressure gap (20) between the shell (2) and the beam (1),
      and being embodied by a floating ring seal whose floating ring (10), the same being disposed in a plane perpendicular to the axis of the shell (100) and being movable in the direction of the latter axis, has at least one chamber (19) which is open towards an inwardly facing rubbing surface (9) corotating with the shell (2), extends in the peripheral direction and is closed in every direction parallel to the plane perpendicular to the roll axis, pressure liquid from the gap (20) between the shell (2) and the beam (1) having access to the chamber (19),
      characterised in that
      a groove (30) which extends over the extent of the end transverse seal (8, 10) in the peripheral direction and is open towards the rubbing surface (9) is provided in the floating ring (10) radially outside the chamber (19) and communicates with the low-pressure side.
2. A seal according to claim 1, characterised in that the floating ring (10) engages by way of an outer axial closed peripheral projection (12) over a diameter step (11) of the beam (1) and there are disposed below the extension (12) a peripheral groove (13) in the beam (1), on the base of the groove an O-ring (14) and thereabove a ring (15) which fills up the width of the groove (13), engages sealingly with the inner periphery (16) of the projection (12) and is made of a low-friction material.
3. A seal according to claim 2, characterised in that the ring (15) is made of polytetrafluoroethylene.
4. A seal according to claim 2 or 3, characterised in that the floating ring (10) has its end face (36) remote from the surface (9) at an axial distance from the diameter step (11) and has its inner periphery (37) at a radial distance from the adjacent zone of the beam (1) and a duct (26) extends from the groove (30) to the floating ring end face (36) facing the diameter step (11).
5. A seal according to claim 2 or 3, characterised in that the floating ring (10) has a number of peripherally consecutive chambers (19, 19, ...) and a duct (32) which is open towards the surface (9) and which, starting from the groove (30), extends radially inwards as far as the low-pressure side.

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